1. Field of Invention
This invention relates to a single rod calculating device having movable counters thereon and corresponding sequentially spaced numerals on said rod.
2. Description of the Prior Art
An abacus is an early development of a manually operable calculating device comprising a plurality of spaced vertically disposed strings having thereon movable counters but there was not present any resulting reading of a calculation.
Where a pupil can physically carry out a calculating function and see what he is doing, the mental process of absorbing and understanding the method of calculating and its result is greatly expedited. This has been attested to by teachers involved in teaching arithmetic to very early grade school children.